So I would like some advise after having seen Linu's video of him altering the airflow in his Wife's PC.

My situation is this:
My case is the CM Storm Enforcer and I have installed two CM SickleFlow 120 on the top of the case as exhaust. This means that the only intake I have is a 200 mm intake in the front of the case, while having three exhaust in the back/top. What I really wanted to know is if it would be optimal to change those three fans into intake instead, and then change the 200mm to exhaust, or even remove it completely.

The reason why I haven't done this is due to those fans not being filtered, so I suspect it will push a lot of dust into my case no?

I also have two side-questions. Sine the two fans I've installed myself is 2k rpm, should I buy some rubber frames to put between them and the case, because frankly, they do make a lot of sound?

The other side question is also whether or not to buy a watercooler for my CPU. Currently my I7-2600 goes at around 75-80 degrees Celsius when gaming SW:TOR while having activated the built-in MSI OC Genie II feature. Is this enough to consider a watercooler for my CPU?

I know that was a lot of questions, but it would be much appreciated if people could give me a bit of advise :) I am no noob with PC's however this is my first serious gaming PC so I am not that much into-the more pro-gaming PC hardware and accessories.

EDIT:
I should also note that I have two GTX 560 in my case which do create a fair amount of heat when gaming.